The present invention concerns a jamb liner for a window assembly, and more particularly concerns a jamb liner configured to provide an air seal against a window frame despite dimensional variations between the window frame and the jamb liner.
Many window frame assemblies include a frame, a jamb liner and a resilient foam block positioned between the jamb liner and the window frame to fill gaps between the jamb liner and the window frame and to thus reduce the flow of air through the window assembly. However, the foam often loses its resiliency over time and takes a permanent set, thus leading to undesirable air leaks. Also, foam can allow the jamb liner to bow, which results in inconsistent and possibly inadequate or excess operational forces on a slideable sash operably positioned in the window assembly. Still further, foam can make the jamb liner more difficult to install.
U.S. Pat. No. 5,265,308 discloses four different jamb liners in FIGS. 1-2, FIGS. 3-4, FIGS. 5-6 and FIG. 7, each having a relatively stiff strip-like member connected to the rear of the jamb liner by a co-extruded spring hinge member comprising resilient material. In the embodiments of FIGS. 1-2, FIGS. 5-6 and FIG. 7, the resilient material is located directly adjacent (extends contiguously along) the rear of a wall defining a sash-engaging guideway in the jamb liner, and in the embodiment of FIGS. 3-4, the resilient material extends contiguously along the rear of a wall defining a close-out/attachment panel at the lateral edge of the jamb liner. In each case, the resilient material extends directly along and immediately adjacent an outer surface of a wall of the jamb liner; however, this can cause several undesirable results which adversely affect the appearance and/or functionality of the wall as well as the operation of the hinge sought to be implemented. Further, this type of arrangement includes a structurally complex elongated hollow tube and or cylinder to which one edge of a finlike strip is attached, such that the tube or cylinder actually provides the bending hinge action. This is believed unduly complex and difficult to co-extrude in a continuous unwarped profile due to differential cooling rates of the resilient material of the hinge and the stiff material of the jamb liner. Another difficulty with such jamb liners is that the resilient hinge members are positioned at an outermost edge of the jamb liner, next to the frame, where they can be contacted by and compressed between the jamb liner and the window frame, which is undesirable.
Thus, an improved jamb liner is desired that provides a resilient hinge member spaced from the sash-engaging or main portion of a jamb liner, which may be utilized to provide a more continuous and gradual resilient biasing effect and/or to provide a positive limiting action to the hinging effect, and which can be readily and consistently manufactured.